al_reconfigure_joysticks

Allegro is able to cope with users connecting and disconnected joystick devices on-the-fly. On existing platforms, the joystick event source will generate an event of type ALLEGRO_EVENT_JOYSTICK_CONFIGURATION when a device is plugged in or unplugged. In response, you should call al_reconfigure_joysticks.

All ALLEGRO_JOYSTICK handles remain valid, but handles for disconnected devices become inactive: their states will no longer update, and al_get_joystick will not return the handle. Handles for devices which remain connected will continue to represent the same devices. Previously inactive handles may become active again, being reused to represent newly connected devices.

It is possible that on some systems, Allegro won't be able to generate ALLEGRO_EVENT_JOYSTICK_CONFIGURATION events. If your game has an input configuration screen or similar, you may wish to call al_reconfigure_joysticks when entering that screen.